GaN system compound semiconductor and method for growing crystal thereof

Abstract

GaN system compound semiconductor and method for growing a crystal thereof, which can significantly reduce a concentration of crystalline defects caused by lattice mismatch by growing a GaN system compound semiconductor of GaN or In x Ga 1-x N by using In x Al 1-x N crystal on a substrate as an intermediate buffer layer, the method including the steps of (1) providing a sapphire substrate, (2) growing an intermediate buffer layer of In x Al 1-x N on the sapphire substrate, and (3) growing GaN or In x Ga 1-x N system compound semiconductor on the intermediate buffer layer.

What is claimed is:  
     
       1. A method for growing, a crystal of a GaN system compound semiconductor, comprising the steps of: 
       (1) providing a sapphire substrate;  
       (2) growing a superlattice structure of In x Al 1-x N/AlN or In x Al 1-x N/GaN on the sapphire substrate as an intermediate buffer layer; and,  
       (3) growing a GaN system compound semiconductor of GaN or In x Ga 1-x N on the intermediate buffer layer.  
     
     
       2. A method as claimed in  claim 1 , wherein the intermediate buffer layer has a thickness of 10˜10,000 Å. 
     
     
       3. A method as claimed in  claim 1 , further comprising the step of forming a protection layer of GaN on the intermediate buffer layer for preventing vaporization of In contained in the intermediate buffer layer before elevating a temperature after the step (2). 
     
     
       4. A method as claimed in  claim 1 , wherein the superlattice structure has 1˜300 layered wherein an In x Al 1-x N layer in the superlattice structure has a thickness of 1˜200 Å and the GaN or AlN layer has a thickness of 1˜200 Å. 
     
     
       5. A method as claimed in  claim 1 , further comprising a protection layer of GaN grown on the intermediate buffer layer for preventing vaporization of In contained in the intermediate buffer layer before elevating a temperature after the intermediate buffer layer is formed.